Definition & Calculation of PES:
→ Definition → Price Elasticity of Supply (PES) measures the responsiveness of quantity supplied to a change in price
→ Formula → PES = % change in quantity supplied ÷ % change in price
→ % Change in Quantity Supplied → [(New Quantity Supplied – Old Quantity Supplied) ÷ Old Quantity Supplied] × 100
→ % Change in Price → [(New Price – Old Price) ÷ Old Price] × 100
→ Positive Value of PES → PES is usually positive due to the Law of Supply (higher prices encourage firms to supply more)
→ Interpretation of PES Values → Standard numerical values reflect the degree of responsiveness of producers
→ Perfectly Inelastic (PES = 0) → Quantity supplied cannot change regardless of price changes
→ Inelastic (0 < PES < 1) → % change in quantity supplied is smaller than the % change in price
→ Unitary Elasticity (PES = 1) → % change in quantity supplied equals the % change in price
→ Elastic (1 < PES < ∞) → % change in quantity supplied is greater than the % change in price
→ Perfectly Elastic (PES = ∞) → Producers will supply any quantity demanded at a constant price, but nothing below it
Example:
→ If market price increases by 20% and a firm expands output from 100 to 130 units (30% increase), PES = +30% ÷ +20% = 1.5 (Elastic supply)
Analysis:
→ Price Signals → High PES means firms can rapidly expand production to capture higher revenues when market prices rise
→ Value Distinction → When PES is greater than 1, supply is responsive; when PES is less than 1, supply is unresponsive
Evaluation:
→ PES calculations rely on current price data, which may fluctuate rapidly in volatile markets
→ A firm’s PES is not constant and will change as production capacity or technology evolves
Supply Curves Showing Different PES:
1. Perfectly Inelastic Supply (PES = 0):
→ Curve Shape → Vertical straight-line supply curve
→ Interpretation → Fixed quantity supplied available regardless of price increases or decreases
2. Inelastic Supply (0 < PES < 1):
→ Curve Shape → Steep supply curve starting from the horizontal (Quantity) axis
→ Interpretation → Large change in price results in a proportionally smaller change in quantity supplied
3. Unitary Elastic Supply (PES = 1):
→ Curve Shape → Any straight-line supply curve passing directly through the origin (0,0)
→ Interpretation → Percentage change in price produces an identical percentage change in quantity supplied
4. Elastic Supply (1 < PES < ∞):
→ Curve Shape → Shallow / flatter supply curve starting from the vertical (Price) axis
→ Interpretation → Small change in price results in a proportionally larger change in quantity supplied
5. Perfectly Elastic Supply (PES = ∞):
→ Curve Shape → Horizontal straight-line supply curve
→ Interpretation → Infinite output supplied at a given price; zero supplied at any lower price
Analysis:
→ Origin Principle → Any linear supply curve intersecting the origin has a PES equal to 1, regardless of its angle
→ Intercept Rule → Supply curves intersecting the vertical axis are price elastic, whereas curves intersecting the horizontal axis are price inelastic
Evaluation:
→ Extreme shapes like vertical or horizontal supply curves are theoretical models, though real-world approximations exist (e.g., stadium seating)
→ Graphs depict ceteris paribus conditions, assuming non-price supply determinants remain unchanged
Determinants of Price Elasticity of Supply:
→ Time Period → Supply is inelastic in the short run due to fixed factors of production, but elastic in the long run as firms expand capacity
→ Availability of Stock / Inventory → Firms holding high levels of finished goods inventory can increase supply quickly (elastic supply)
→ Production Lag / Speed of Production → Goods requiring long manufacturing processes (e.g., agricultural crops) have inelastic supply
→ Spare Capacity → Firms operating below maximum capacity can easily scale up output when prices rise (elastic supply)
→ Mobility of Factors of Production → Reallocating occupational or geographical labor and raw materials easily makes supply more elastic
→ Flexibility of Production Technology → Multi-purpose machinery enables rapid product switching, increasing supply elasticity
Example:
→ Fresh agricultural produce like strawberries has an inelastic supply due to crop growing time, whereas manufactured goods like t-shirts have elastic supply
Analysis:
→ Capacity Constraints → Operating at 100% capacity restricts immediate output expansion, creating price inelastic supply in the short term
→ Storage Characteristics → Perishable goods cannot be stored for long periods, lowering stock availability and making supply inelastic
Evaluation:
→ Technological advancements (e.g., 3D printing, automated assembly) increase factor mobility, making modern supply more elastic
→ External shocks like supply chain disruptions can temporarily reduce supply elasticity even for flexible industries
Significance of PES in Economics:
1. Producers & Businesses:
→ Competitive Advantage → Increasing PES allows firms to react faster than rivals to market price changes and consumer demand shifts
→ Strategic Adjustments → Maintaining spare capacity and flexible inventory storage improves market responsiveness and revenue growth
2. Governments:
→ Impact of Indirect Taxes → Imposing indirect taxes on goods with inelastic supply causes a larger drop in price received by producers than market quantity traded
3. Primary Product Markets:
→ Price Volatility → Agricultural products have inelastic supply, leading to severe price fluctuations following unexpected demand or supply shifts
Analysis:
→ Market Adjustments → Highly elastic supply prevents price spikes by quickly accommodating shifts in demand through output changes
→ Revenue Stability → Flexible firms with high PES avoid sharp income declines during economic downturns by reducing output rapidly
Evaluation:
→ Building excess stock or keeping spare capacity to increase PES raises storage and overhead costs for businesses
→ Primary commodity producers often face structural barriers (e.g., land limits) that prevent long-term increases in PES